<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <script src="https://cdn.staticfile.org/react/16.4.0/umd/react.development.js"></script>
    <script src="https://cdn.staticfile.org/react-dom/16.4.0/umd/react-dom.development.js"></script>
    <!-- 生产环境中不建议使用 -->
    <script src="https://cdn.staticfile.org/babel-standalone/6.26.0/babel.min.js"></script>
    <title>购物车加减</title>
    <style>

    </style>
</head>

<body>
    <div id="app"></div>

</body>
<script type="text/babel">
    class NumberText extends React.Component{
        constructor(){
            super()
            this.state = {
                number:5
            }
        }

        last(){
            this.setState({
                number: this.state.number == this.props.min ? Number(this.props.min) : (this.state.number - 1) 
            })
        }

        next(){
            this.setState({
                number: this.state.number == this.props.max ? Number(this.props.max) : (this.state.number + 1)
            })
        }


        render(){
            return (<div>
                        <input type="button" value="-" onClick={this.last.bind(this)}/> 
                        <span>{this.state.number}</span>
                        <input type="button" value="+" onClick={this.next.bind(this)}/>
            </div>)
        }
    }

    ReactDOM.render(<NumberText min='0' max='12' />,app)
</script>

</html>